Re: set and dict iteration

Newsgroups	comp.lang.python
Date	2012-09-08 08:42 -0700
References	(13 earlier) <mailman.154.1346700607.27098.python-list@python.org> <mailman.155.1346702665.27098.python-list@python.org> <504558cb$0$29978$c3e8da3$5496439d@news.astraweb.com> <mailman.162.1346723805.27098.python-list@python.org> <50456073$0$29978$c3e8da3$5496439d@news.astraweb.com>
Message-ID	<87f103a7-2bbd-405f-8a5e-3aaf02c80fff@googlegroups.com> (permalink)
Subject	Re: set and dict iteration
From	Aaron Brady <castironpi@gmail.com>

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On Monday, September 3, 2012 8:59:16 PM UTC-5, Steven D'Aprano wrote:
> On Mon, 03 Sep 2012 21:50:57 -0400, Dave Angel wrote:
> 
> 
> 
> > On 09/03/2012 09:26 PM, Steven D'Aprano wrote:
> 
> 
> 
> >> An unsigned C int can count up to 4,294,967,295. I propose that you say
> 
> >> that is enough iterators for anyone, and use a single, simple, version
> 
> >> counter in the dict and the iterator. If somebody exceeds that many
> 
> >> iterators to a single dict or set,
> 
> > 
> 
> > I think you have the count confused.  it has to be a count of how many
> 
> > changes have been made to the dict or set, not how many iterators exist.
> 
> 
> 
> Oops, yes you are absolutely right. It's a version number, not a count of 
> 
> iterators.
> 
> 
> 
> 
> 
> -- 
> 
> Steven

Hello.  We have a number of proposed solutions so far.

1) Collection of iterators
  a) Linked list
    i) Uncounted references
    ii) Counted references
    iii) Weak references
  b) Weak set
2) Serial index / timestamp
  a) No overflow - Python longs
  b) Overflow - C ints / shorts / chars
  c) Reset index if no iterators left
3) Iterator count
  - Raise exception on set modifications, not iteration

Note, "2b" still leaves the possibility of missing a case and letting an error pass silently, as the current behavior does.  The rest catch the error 100% of the time.

Anyway, I plan to develop the above patch for the 'dict' class.  Would anyone like to take over or help me do it?

Thread

Re: set and dict iteration Ian Kelly <ian.g.kelly@gmail.com> - 2012-08-27 13:17 -0600
  Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-09-02 10:43 -0700
    Re: set and dict iteration Ian Kelly <ian.g.kelly@gmail.com> - 2012-09-03 13:29 -0600
      Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-09-03 13:04 -0700
        Re: set and dict iteration Dave Angel <d@davea.name> - 2012-09-03 16:27 -0400
          Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-09-03 17:24 -0700
          Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-09-03 17:24 -0700
      Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-09-03 13:04 -0700
        Re: set and dict iteration Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-09-04 01:26 +0000
          Re: set and dict iteration Dave Angel <d@davea.name> - 2012-09-03 21:50 -0400
            Re: set and dict iteration Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-09-04 01:59 +0000
              Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-09-08 08:42 -0700
  Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-09-02 10:43 -0700

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